Polyphenylene ether resins have been modified with polyamide resins to provide a wide variety of beneficial properties such as heat resistance, chemical resistance, impact strength, hydrolytic stability and dimensional stability compared to either unmodified resin alone.
U.S. Pat. No. 4,923,924 to Grant et al. generally describes a composition comprising a polyamide, a carboxylated polyphenylene ether, and an impact modifier.
U.S. Pat. No. 5,109,052 to Kasai et al. generally describes a thermoplastic composition comprising a polyphenylene ether, a polyamide, and a specific block copolymer, wherein the PA forms a continuous phase, the PPE is dispersed in the PA, and the block copolymer is micro-dispersed in the PPE.
U.S. Pat. No. 5,977,240 to Marie Lohmeijer et al. generally describes a thermoplastic composition comprising (a) a compatibilized polyphenylene ether-polyamide base resin, and (b) 1–7 parts by weight per 100 parts by weight of (a) of an electroconductive carbon black, with an Izod notched impact strength of more than 15 kJ/m2 and a volume resistivity of less than 106 Ohm-cm.
U.S. Pat. No. 6,171,523 to Silvi et al. generally describes a method for the preparation of conductive polyphenylene ether-polyamide compositions, the method comprising melt blending polyphenylene ether, an unsaturated impact modifying polymer and a functionalizing compound in an initial step, optionally in combination with a portion of the polyamide, and subsequently melt blending with the remainder of the polyamide and conductive carbon black having a low volatiles content.
U.S. Pat. No. 6,221,283 to Dharmarajan et al. generally describes a method of making a conductive thermoplastic composition containing at least one dispersed phase polymer with a continuous phase polymer and at least one conductivity imparting agent, wherein the bulk resistivity of the composition is at least partially determined by the particle size of the dispersed phase within the continuous phase. The thermoplastic composition preferably comprises a compatibilized blend of at least one polyphenylene ether resin, at least one polyamide resin, and at least one conductivity imparting agent, and optionally, one or more of impact modifiers, stabilizers, antioxidants, lubricants, and fillers.
European Patent Application 627,466 A2 to Campbell et al. generally describes incorporation of high glass transition temperature polyphenylene ethers in immiscible polymer blends to yield increased heat deflection temperatures.
The use of compatibilized polyphenylene ether-polyamide compositions for painted automobile exterior parts has led to increased demands for high-temperature dimensional stability, so that molded parts can tolerate higher temperatures in paint-drying ovens. However, other physical properties, such as impact strength and electrical conductivity, cannot be compromised in the pursuit of improved thermal resistance. There therefore remains a need for polyphenylene ether-polyamide compositions exhibiting improved balances of thermal resistance, impact strength, and electrical conductivity.